This invention relates to a connector system for fibre optic male contacts having an elongated ferrule for centrally housing an end portion of a fibre optic core.
European Patent Application No EP-A-0398161 describes such a fibre optical connector comprising a standard two-part connector for printed circuit boards having a plug shell inserted into a socket shell provided with a plurality of opposed cavities for separate contacts. The plug shell cavities are equipped with socket shell hollow inserts allowing a more accurate alignment of said ferrules.
U.S. Pat. No. 5,195,905 discloses a connecting device including two tubular bodies each of which is connected to a conductor of electrical or of similar signals. The device comprises automatic engagement locking means and manual disengagement means.
Such systems are commonly used for optically coupling optic fibres to each other. They require however a precise environment for proper front to front alignment of the ferrules of the fibre optic male contacts.
EP-A-0398161 describes such a fibre optical connector comprising a standard two-part connector for printed circuit boards having a plug shell inserted into a socket shell provided with a plurality of opposed cavities for separate contacts. The plug shell cavities are equipped with socket shell hollow inserts allowing a more accurate alignment of said ferrules.
U.S. Pat. No. 5,195,905 discloses a connecting device including two tubular bodies each of which is connected to a conductor of electrical or of similar signals. The device comprises automatic engagement locking means and manual disengagement means.
It is an object of this invention to enlarge the possibilities of use of these fibre optic male contacts by means of a connector system which is versatile, cheap and easy to supply while providing high quality fibre optic performance.
According to a first aspect of the invention, there is provided a connector system for fibre optic male contacts having an elongated ferrule for centrally housing an end portion of a fibre optic core, comprising a standard two-part connector for printed circuit boards having a plug shell inserted into a socket shell, said shells having grids and a plurality of opposed cavities for separate contacts, a front plug shell hollow insert and a rear plug shell hollow insert assembled in communication to one another in a cavity of the plug shell, and a floating alignment sleeve characterised in that it comprises a front socket shell hollow insert and a rear socket shell hollow insert assembled in communication to one another in a cavity of the socket shell opposed to said cavity of the plug shell, in that said front socket shell insert has a first portion engaged into said cavity of the socket shell and a second portion engaged into said front plug shell insert and in that said floating alignment sleeve extends at least in one of said front plug shell insert and front socket shell insert for front to front aligned housing of the ferrules of two fibre optic male contacts respectively plugged into said rear plug shell insert and rear socket shell insert.
Accordingly, a connector system is obtained which enables high performance fibre optic male contacts to be used in conjunction with standard unmodified printed circuit boards connectors. While still offering the convenience of printed circuit boards use, the system enables telecommunication quality fibre optic performance to be achieved. The fully floating ferrule alignment mechanism provides excellent mechanical, environmental and optical performance despite the relatively poor precision of the standard two-part connector. The supply and termination of the connector system are particularly advantageous and the system is suitable for a variety of applications, including industrial, military, deployable communication, instrumentation, shipboard, aerospace, broadcast, high energy physics, medical, motor-sports, telecommunications, and data-communications. The system is applicable to singlemode and multimode applications and target performance is excellent on the viewpoint of insertion loss, back reflection, temperature cycling, shock, repeatability, connector durability, humidity resistance, and vibration.
According to a further aspect of the invention, the rear plug shell insert is rotatively mounted in said cavity of the plug shell and has a first portion with an inner thread and a second portion forming a collar resting against an external shoulder formed around said cavity, and the front plug shell insert has a first portion with an outer thread meshing into the inner thread of the first portion of the rear plug shell insert and a second portion in sliding fit in said cavity, said second portion of the front plug shell insert ending in a collar resting in an external groove formed around said cavity. In a preferred arrangement, said second portion of said front plug shell insert has longitudinally extending external grooves engaged on longitudinal ridges formed in said cavity.
According to a further aspect of the invention, the front socket shell insert has its first portion rotatively mounted in said cavity of the socket shell said first portion having an inner thread and resting against an inner shoulder of said cavity, and said rear socket shell insert has its first portion in sliding fit in said cavity and with an outer thread meshing into the inner thread of the first portion of the front socket shell insert and a second portion resting against said socket shell. Preferably, said second portion of the rear socket shell insert has a polygonal collar resting between external ridges formed around said cavity. Still preferably, the front socket shell insert has its second portion engaged into said second portion of the front plug shell insert.
In a preferred arrangement, the connector system further comprises a tubular sleeve retainer having a first portion affixed in said first portion of the front plug shell insert and a second portion engaged into said second portion of the front socket shell insert, wherein the alignment sleeve is floating in said tubular sleeve retainer. The first portion of the tubular sleeve retainer may be press-fitted into said first portion of the front plug shell insert.
The rear plug shell insert and the rear socket shell insert may each have a circular transverse inner latch catching groove, while each of said fibre optic male contacts is mounted in a plug adapted to be inserted into said rear plug shell insert or rear socket shell insert, said plug having radially movable resilient latches for insertion into said latch catching grooves. In a further embodiment, inclined surfaces are formed on said latches and wall means may be arranged on said plug for urging the latches against the resiliency thereof. A control sleeve may be mounted for longitudinal movement on said plug, with said wall means being connected to said control sleeve. A longitudinal inner groove may be arranged in each of said rear plug shell insert and rear socket shell insert, with a radial stud being arranged on said control sleeve for sliding fit insertion into said grooves.
These and other objects, features and advantages of the invention will become readily apparent from the following detailed description with reference to the accompanying drawings which show, diagrammatically and by way of example only, a preferred but still illustrative embodiment of the invention.